Hot-filament magnetic rectifier



July 27 1926. 1,594,060

J. HUFF HOT FILAMENT MAGNETIC RECTIFIER Filed June 21. 1918 2Sfiee'cs-Sheet 1 July 27,1926. 1,594,060

, J. HUFF HOT FILAMENT MAGNETIC RECTIFIER Filed June 21.1518 2Sheets-Sheet 2 Fig.6.

V A A a n r InVentor I I Jesse Huff,

His Attorney.

Patented 1 July 27, 1926.

UNITED STATES PATENT OFFICE.

JESSE HUFF, OF NEW YORK, N. Y., ASSIGNOR TO GENERAL ELECTRIC COMPANY, OFSOEENEOTADY, NEW YORK, A CORPORATION OF NEW YORK.

HOT-FILAMENT MAGNETIC RECTIFIER.

Application filed June 21, 1918. Serial No. 241,231.

The present invention relates to that class of electrical instrumentswhich depend for their operation upon the emission of negatively chargedcorpuscles or electrons from heated metals and more particularly todevices of this character which are used for the rectification ofalteranting current.

It is the object of this invention to produce a device of thecharacteristics referred to for completely rectifying alternatingcurrent and thus make the whole output of a source of alternatingcurrent available for consumption as direct current.

The principles upon which the invention is based will be more clearlyexplained in the specification and the essential features moreparticularly'pointed out in the claims.

In the drawings which formapart of the specification Figure 1 is adiagrammatic view of an arrangement showing an embodiment of theinvention in side elevation;

Figure 2 is a lan view of the arrangement shown in Figure 1;

Figure 3 is a diagrammatic view similar to Figure 1 showing certainmodifications;

Figures 4: and 5 are diagrams illustrating certain physical phenomena;and

Fig. 6 illustrates a modification suitable for operation withalternating current.

As is well. known, the rectifying action of a device composed of a hotfilament-cathode and a metal anode in a substantially perfeet vacuum isdue to the unidirectional conductivity of the device, the current beingcarried only by the electrons emitted by the hot filament.

An electron in motion constitutes an element of an electric current.Such an lec tron in motion is surrounded by a circular magnetic fieldprecisely as a conductor carrying current is surrounded by a magneticfield. Assume that in Figures 1 and 5 the dot 1 represents an electronand that in Figure 4 the direction of electronic movement is downwardlyinto the sheet away from the observer, while in Figure 5 this movementis toward the observer. In thefirst case the magnetic lines of force 2surround the electron in clockwise direction, whilein the. latter casethe magnetic lines 2' have a counter-clockwise direction.

If a unidirectional magnetic flux, indicated by the arrow lines, ispassed in a direction perpendicular to the direction of electronicmigration, it will be seen that in the first case (Figure 4:) thereaction of the two fields will result in a force acting on the electron1 in a direction along the sheet and toward its lower edge, as indicatedby the arrow 4, while in the second case (Figure 5) the resultant forcewill be oppositely directed. The rate at which the force will causetheelectron to deviate from its original path will, of course, depend uponthe relative values of the forces producing motion into the sheet andalong the sheet respectively. In either case the force due to theinteraction of the magnetic fields may be regulated by altering themagnetic field intensity.

In Figures 1 and 2, which are purely diagrammatic representations, 5indicates a magnet having its poles 6 and 7 facing each other to definea distinct magnetic field of relatively great intensity. On oppositesides of the magnetic field are metallic filaments 8 and 9 which may beheated electrically by batteries 10 and 11 respectively or by smalltransformers as is well understood. The secondary 13 of a step uptransformer 12 from which the alternating current to be rectified isderived hasone' side connected}directly to one of the filaments, say tothe filament 8, and the other side through ground to the other filament.Below and above the magnetic field are placed the metallic anodes ortargets 14 and 15 respectively, which are interconnected by a conductor16 and have a common connection 17 to one terminalof a load device, theother terminal of the load device being grounded. The targets'H and 15and the filanients 8 and 9 are inclosed in a vacumn chamber 18,indicated in dotted lines in Fig. 1. Since magnetic flux passes readilythrough glass, the magnet poles 6 and 7 may be placed outside thereceptacle in which the vacuum is produced.

The operation ofthe device is as follows:

The hot filament 8 is charged ne atively during one alternation and thehot filament 9 during the other alternation of each cycle. An electricmigration will therefore take place in turn from each of the hotfilaments; to a target. As has been explained in connectionwith Figures4 and 5, the magnetic lines intercepting the path of the electrons Citwill force the electrons coming from one of the filaments downwardlytoward the target ll and the electrons coming from the other filamentupwardly toward the target 15. Assuming the pole 6 to be north and thepole 7 to be south, the electrons coming from the cathode 8 will beforced toward target 14 and the electrons coming from cathode 9 will beforced up toward target 15. The thermionic current thus produced willflow alternatel from the targets ll and 15 through the common connection17 to the load device.

The magnetic deflection of the electrons in opposite directions has theadvantage that two targets may be employed whereby the heat dissipatingsurface is doubled. It the magnetic field is made to alternate, only asingle target is necessary, since the resultant of the magnetic lines offorce would have the same direction in both cases. Fig. 6 illustratessuch an arrangement, the device 23 being provided with a single anode24, and the magnet 25 being provided w th a magnetizing winding 26 towhich a suitable alternating current is supplied, in this case by theconductors 27, 28.

The device shown in Figure 3 is essentially the same as that shown inFigure 1, differing therefrom only as to the mode of interconnecting theparts.

In Figure 3 the one end of the secondary 20 is connected to the filament21 and the other end to the filament 22, while the center point of thesecondary is connected to ground. While in the device of Figure 1 onefilament has to be insulated against the total voltage and the totalvoltage is impressed on the load, in the device of Figure 3 bothfilaments need be insulated a ainst only one half of the total voltagean? only one half of the total voltage is impressed on the load device.

It is understood that various changes may be made within the scope ofthe disclosure.

I claim:

1. The combination with a source of al ternating current and a. loaddevice of an evacuated vessel, an electrode of the hot cathode typecapable of emitting electrons, and another electrode in the vessel, aconnection between one pole of the said source and the hot cathode, aconnection between the second electrode and one terminal of the loaddevice, a connection between the second p le of the source and the otherterminal of v the load device, and means for producing a magnetic fieldhaving a component substantially normal to the electron flow forcontrolling the electron migration between the two electrodes.

The combination with a source of alternating current and a load device,of an evacuated vessel, two electrodes of the hot cathode type and twocold electrodes positioned to co-operate one with one of the hotcathodes and the other with the other hot cathode, means for producing amagnetic field intermediate the electrodes'for controlling the flow ot'the thermionic current bctween the respective pairs of electrodes, aconnection between one pole of the said source and one of the hotcathodes, a connection between the opposite pole of the source and theother hot cathode and a circuit connection between the two coldelectrodes, and a connection between said circuit connection and thesource including the load device.

3. A current rectifier comprising an evacuated vessel, two pairs ofelectrodes, one electrode of each pair being of the hot cathode type, aconductor connected to one of the hot cathodes and extending through thewall of the vessel, a conductor connected to the other hot cathode andextending through the wall of the vessel, a circuit connectioninterconnecting the two other electrodes, a conductor extending fromsaid circuit connection and having at least a portion lying outside thevessel and means for producing a magnetic field substantially normal tothe electron flow for controlling the flow of the thermionic currentbetween the pairs of electrodes.

4. A current rectifier comprising an evacuated vessel, two conductorstherein connected to opposite poles of a source of alternating current,means for heating each of said conductors to cause an emission ofelectrons therefrom, a third conduct-or positioned at an angle to bothof said conductors, means for establishing a connection between saidthird conductor and the source of current and means for producing-amagnetic field in the path of the electrons to control their ath ofmigration relatively to the third con uctor.

5. A current rectifier comprising an evacuated vessel, two conductorstherein connected to opposite poles of a source of alternating current,means for heating each of said conductors to cause an emission ofelectrons therefrom, two relatively cold conductors symmetricallylocated relatively to the hot conductors at an angle thereto, means forestablishing a common connection between the said cold conductors andthe source of current and means for producing a magnetic field in thepath of the electrons to control the course of migration between theheated conductors and the relatively cold conductors.

6. A current rectifier comprising two hot cathodes connected to oppositepoles of a source of alternating current, two metallic anodes disposedon a line which is substantially perpendicular to the line between thecathodes, said anodes being substantially perpendicular to said line,and a magnet for producing a field substantially at right angle .to bothsaid lines and intercepting both of said lines.

7. A current rectifier comprising evacuated container, two hot cathodestherein positioned Opposite one another, a separate anode associatedwith each of said cathodes, each anode being located inelectron-receiving relation to its associated cathode, means forsupplying an alternating potentialvto said cathodes, and means forproducing a magnetic field having a component substantially at rightangles to the direction of the electron flow to thereby selectivelydirect the electron migration between each cathode and its associatedanode.

8. A current rectifier comprising two hot cathodes capable of emittingelectrons, a source of alternating current connected to said cathodes,two metallic anodes, one of said anodes being adapted to cooperate withone of said cathodes and the other of said anodes being adapted tocooperate with the other of said cathodes, and means for producing amagnetic field to selectively direct the electron migration fromeach-cathode to said two'electrodes, means for producing a magneticfield to direct the flow of electron current from each of said twoelectrodes relatively to said cooperating electrode.

In testimony whereof, I afiix my signature.

JESSE HUFF.

